Lec-1 Introduction and Fundamental Concepts
There is always a rhythm for all physical processes in nature to occur. Even the random motions
of molecules have got a typical correlation coefficients or correlations. There are many
processes which can be caused to occur in both the directions. For example, the conversion of
mechanical energy into heat or intermolecular energy is possible. All natural processes occur
with certain rhythm. There are certain natural laws or natural constraints imposed on these
processes. The conversion of energy is not efficient in all directions. The relationships between
physical properties of these systems which are affected by these processes are also being
established by this science of thermodynamics. The thermodynamics is a fundamental subject
that describes the basic laws governing the occurrence of physical processes associated with
transfer or transformation of energy and establishes the relationship between different physical
properties which are being affected by these processes. This is the domain of thermodynamics.
In thermodynamics, there are two views. One is macroscopic views another is microscopic or
statistical views.
The relationship is very simple that macroscopic behavior is always explained through the
behavior of individual molecules. This is because any matter or substance is composed of
number of molecules. Any theory in microscopic behavior may change but this has to be
calibrated against the microscopic behavior. For example, pressure is because of the change of
momentum due to molecular collision that means if we want to find out the pressure exerted by
the fluid on a wall we just explain from a molecular point of view that it is the time average. The
thermodynamics is a subject which establishes the relationship between different properties
when there is a change in the properties because of a process occurring due to the interactions
between the system and the surroundings. So Maxwell ’ s equations, Tds equations , difference
in heat capacities , ratio of heat capacities. Joule-Kelvin effect. Then properties of pure
substances , a part of which already we have studied in physics , phase equilibrium diagram
different thermodynamic planes p-v , p-T. Then dryness fraction, steam tables , Mollier
diagram , these are things we will know afterwards. Air standard cycles : Carnot , Stirling ,
Ericssion , Otto , Diesel , Dual and Brayton cycles. There are extended cycles and vapor cycles.
The extended cycles deal with air as the working system. Vapor cycles deals with vapor that
means the system which changes from liquid to vapor phase as it goes around the cycle. Carnot
cycle: simple Rankine cycle. Reheat and regenerative cycles: vapor compression refrigeration
cycles.
There is a concern for efficient utilization of the natural resources of fossil fuels. At the same
time, we are concerned today about the environment. We want a clean environment that means
whenever we transform energy to get power from its fossil fuel terms of chemical energy, geo
thermal energy or that energy stored in that in mechanical power. In thermodynamics we can
find out things which can not be done which comes from the law of nature. So with this now I will
start course , this subject. Very first I will recapitulate the definition of systems. How do we
define a system ? Because in thermodynamics , whatever analysis will be done will be referred
to a system. So a system has two characteristic features certain quantity of matter and
There is always a rhythm for all physical processes in nature to occur. Even the random motions
of molecules have got a typical correlation coefficients or correlations. There are many
processes which can be caused to occur in both the directions. For example, the conversion of
mechanical energy into heat or intermolecular energy is possible. All natural processes occur
with certain rhythm. There are certain natural laws or natural constraints imposed on these
processes. The conversion of energy is not efficient in all directions. The relationships between
physical properties of these systems which are affected by these processes are also being
established by this science of thermodynamics. The thermodynamics is a fundamental subject
that describes the basic laws governing the occurrence of physical processes associated with
transfer or transformation of energy and establishes the relationship between different physical
properties which are being affected by these processes. This is the domain of thermodynamics.
In thermodynamics, there are two views. One is macroscopic views another is microscopic or
statistical views.
The relationship is very simple that macroscopic behavior is always explained through the
behavior of individual molecules. This is because any matter or substance is composed of
number of molecules. Any theory in microscopic behavior may change but this has to be
calibrated against the microscopic behavior. For example, pressure is because of the change of
momentum due to molecular collision that means if we want to find out the pressure exerted by
the fluid on a wall we just explain from a molecular point of view that it is the time average. The
thermodynamics is a subject which establishes the relationship between different properties
when there is a change in the properties because of a process occurring due to the interactions
between the system and the surroundings. So Maxwell ’ s equations, Tds equations , difference
in heat capacities , ratio of heat capacities. Joule-Kelvin effect. Then properties of pure
substances , a part of which already we have studied in physics , phase equilibrium diagram
different thermodynamic planes p-v , p-T. Then dryness fraction, steam tables , Mollier
diagram , these are things we will know afterwards. Air standard cycles : Carnot , Stirling ,
Ericssion , Otto , Diesel , Dual and Brayton cycles. There are extended cycles and vapor cycles.
The extended cycles deal with air as the working system. Vapor cycles deals with vapor that
means the system which changes from liquid to vapor phase as it goes around the cycle. Carnot
cycle: simple Rankine cycle. Reheat and regenerative cycles: vapor compression refrigeration
cycles.
There is a concern for efficient utilization of the natural resources of fossil fuels. At the same
time, we are concerned today about the environment. We want a clean environment that means
whenever we transform energy to get power from its fossil fuel terms of chemical energy, geo
thermal energy or that energy stored in that in mechanical power. In thermodynamics we can
find out things which can not be done which comes from the law of nature. So with this now I will
start course , this subject. Very first I will recapitulate the definition of systems. How do we
define a system ? Because in thermodynamics , whatever analysis will be done will be referred
to a system. So a system has two characteristic features certain quantity of matter and
